Where is the cooling fan on a Hitachi Ultravision TV

SOURCE: I Have a Hitachi Ultravision projetion TV Ned help to fix it.

This sounds like the solder joints on one of the convergence output IC's have cracked loose or the IC itself is defective and quitting when it warms up. The IC needs to be either resoldered or replaced.

SOURCE: hitachi ultravision

Check IC601, C603 for leakage, I601 and vertical pulse detector QN05

for poor convergence check RK42 for open circuit.

SOURCE: PROJECTION TV HITACHI ULTRAVISION COLOR CONVERGENCE PROBLEM

it sounds like your blue convergence ic is getting weak you need to replace the ic's STK392-110 and you should replace both because when 1 is bad the other will go real soon. They are inexspensive at the sight I posted and you will also get free tech online support if you purchase them there.
http://servicemanuals.vstore.ca/

SOURCE: remove screen from Hitachi Ultravision

underneath screen remove screws holding screen in place ,it should then slide upward and off.

SOURCE: hitachi ultravision tv

tv comes on ,i hear but can not see